Handheld device promises to find the gluten in your food (hands-on)

The Nima sensor (left) detects if there's any gluten in a food sample you put in the capsule (right).

Chris Monroe/CNET

Gluten-free food options have become commonplace on restaurant menus and grocery store shelves. But how much can you trust a label? A new gadget aims to put a food's gluten truth right in your hands.

The Nima is a handheld, Bluetooth-connected device that analyzes tiny samples of your food to find out if there's any gluten in what you're about to eat. The Nima first became available for preorder in October 2015, and it's now shipping to customers. Didn't preorder? The company that makes the Nima sells starter kits for $279.

The Nima has two parts: a capsule and a palm-size, wedge-shaped sensor that's 3.5 inches long and 3.1 inches tall. You put a pea-size piece of the food you want to test into the capsule, screw on the lid to grind up your food sample, and put the capsule into the sensor. You press capsule's only button, which makes the food mix with a solution at the bottom of capsule. That mixture reacts with a test strip on the capsule (kind of like a pregnancy test), and the sensor reads the strip for you. After about three minutes and some whirring from inside the sensor, a smiley face pops up on the sensor's OLED screen if the device finds less than 20 parts per million of gluten in the sample (the FDA definition of gluten-free). Any more than that, and the sensor displays a wheat symbol.

You can only use the capsules once, and they're not recyclable. That means that frequent testing could come at a heavy price -- a Nima subscription for 12 capsules a month costs about $60, or $5 a capsule.

The Nima uses Bluetooth to connect with an iOS app where you can keep a record of your test results (Nima's makers said they're trying to release an Android version of the app soon). The app takes a cue from the review site Yelp -- you can upload results of packaged and restaurant food you've tested so other people can see what dishes and restaurants to visit or avoid.

For the past several years, it's been hard to talk about food, diets or nutrition without a mention of gluten, a protein found in wheat, rye and barley. There's been a growing awareness of people with celiac disease, an autoimmune disorder in which eating gluten can lead to damage in the small intestine, according to the Celiac Disease Foundation. The foundation estimates that 1 percent of people worldwide have the condition, and that doesn't include people who have allergies or sensitivities to gluten.

Some of the challenges of gluten testing are already apparent in my initial testing of the Nima. Its creators recommend washing your hands and keeping the Nima clear of food when you test samples to help prevent cross-contamination if you're around food that does have gluten. It's easy to prevent stray gluten from making its way into a Nima capsule when I'm in the test lab. But I could see this being a tougher to keep contaminants away from your sample when you're in a restaurant or other social environment. So, in theory, a stray bread crumb on your restaurant table could skew your test results if it contaminates a bit of food that really is gluten free.

There's also concern (for example, this entry from the Gluten Free Watchdog website) that the small sample you use to test might not detect gluten that's on another part of your food. Let's say you wanted to test a box of crackers that have a gluten-free label. The pea-size test sample from one cracker might not have any gluten, but what if another cracker in the box has traces of gluten? Or what if the entire box is gluten free, but you put your crackers on a plate on which someone else made a sandwich?

Nima spokeswoman Heather Sliwinski said the device is meant to be an additional tool for folks who follow a gluten-free diet rather than replace what they're already doing, such as talking directly to the person who prepared the food in question. "It's true that Nima cannot guarantee an entire dish is gluten-free, since Nima takes a sample of food from your dish," she said. "With any form of testing, whether Nima or lab, you can't guarantee the dish, the box or the lot you didn't test is gluten-free based on one test result."

I will address these issues and continue to test different foods and write a full review soon. So far, it's been accurate with the foods I've tested as control samples. A piece of wheat bread prompted the Nima screen to display two wheat symbols, which means it detected a high level of gluten. And a smiley face popped up when I tested a piece of orange bell pepper. I will continue to test different foods and write a full review soon.